Home entertainment systems have been provided that can include a set-top box media server that communicates with various components in the home, e.g., TVs, laptop computers, and custom display devices. To establish network communication paths, power line communication (PLC) networks have been introduced and have gained in popularity owing to the fact that the home's existing AC power grid is used to also carry entertainment data between various components in the home entertainment system which are plugged into AC wall sockets. In this way, no new wiring is required, rendering most home power grids into effective network backbones.
The present invention makes the following critical observation. Most U.S. homes use a single-phase three-line electricity system in which three lines (L1 and L2 “hot” lines at 120 volts each, plus a neutral line) are provided to each home. Sockets in the home are 120 volt sockets that have two or three connections, one to neutral and one to the L1 line or the L2 line and, when three connections are provided, the third to ground. Some 240 volt sockets may also be provided for 240-volt appliances, for example, for laundry dryers, with a 240 volt socket being connected to both the L1 and L2 lines in an additive fashion to produce the desired 240 volt power supply.
As critically recognized herein, when a PLC transmitter is plugged into a socket connected to, e.g., the L1 line, and a PLC receiver is plugged into a socket that is connected to other (e.g., L2 ) line, cross phase communication occurs that can result in significant signal attenuation, indeed of twenty decibels or more. This undesirable outcome significantly reduces network bandwidth. With these critical recognitions in mind, the present invention is provided.